ACT 09-13 BMW 135i / 09-13 335i XACT Flywheel ProMass

Noticeably improved engine response and acceleration, OE to mild gear rattle; Heat-treated forging for strength and toughness, induction-hardened ring gears for maximum life; One piece construction allows less opportunity for failure and provides uniform efficient heat transfer from the clutch disc. No more warped inserts or loose ring gears; Recommended for street and race use; Forged, CNC machined and dynamically computer balanced for smooth high RPM reliability